Massively parallel sequencing has revolutionized many areas of biology but sequencing large amounts of DNA in many individuals is cost-prohibitive and unnecessary for many studies. Genomic complexity reduction techniques such as sequence capture and restriction enzyme-based methods enable the analysis of many more individuals per unit cost. Despite their utility, current complexity reduction methods have limitations, especially when large numbers of individuals are analyzed. Here we develop a much improved restriction site associated DNA (RAD) sequencing protocol and a new combinatorial method called Rapture (RAD capture). The new RAD protocol improves versatility by separating RAD tag isolation and sequencing library preparation into two distinct steps. This protocol also recovers more unique (non-clonal) RAD fragments and produces better data for both standard RAD and Rapture analysis. Rapture then uses an in-solution capture of chosen RAD tags to target sequencing reads to desired loci. Rapture combines the benefits of both RAD and sequence capture, i.e. very inexpensive and rapid library preparation for many individuals as well as high specificity in the number and location of genomic loci analyzed. Our results demonstrate that Rapture is a rapid and flexible technology capable of analyzing a very large number of individuals with minimal sequencing and library preparation cost. The methods presented here should improve the efficiency of genetic analysis for many aspects of agricultural, environmental, and medical science.

This is very much about the methods, but there’s some interesting fish-genomics results, too. More of that in the next year or so. We can’t all be human or model-organism biologists, so this is excellent for those working in ecological, conservation, and more broadly non-model contexts. For a lot of this work, and population-genomic research as well, you don’t need medical-grade 30✕ whole genome coverage. That being said, this being a pre-print which is going to be revised and submitted, I’d suggest that Omar remove the stuff about medical utility. That’s a domain where they’ll kill them with coverage and the best technology, not the most cost-effective one.